The circular economy (CE) has been a European Union (EU) priority since 2014, when first official document on the CE was published. Currently, the EU is on the road to the transformation from a linear economy model to the CE model. In 2019, a new strategy was announced – the European Green Deal, the main goal of which is to mobilize the industrial sector for the CE implementation. The CE assumes that the generated waste should be treated as a secondary raw material. The paper presents an analysis of the possibility of using selected groups of waste for the production of fertilizers. Moreover, an identification of strengths and weaknesses, as well as market opportunities and threats related to the use of selected groups of waste as a valuable raw material for the production of fertilizers was conducted. The scope of the work includes characteristics of municipal waste (household waste, food waste, green waste, municipal sewage sludge, digestate), industrial waste (sewage sludge, ashes from biomass combustion, digestate) and agricultural waste (animal waste, plant waste), and a SWO T (strengths and weaknesses, opportunities and threats) analysis. The fertilizer use from waste is determined by the content of nutrients (phosphorus – P, nitrogen, potassium, magnesium, calcium ) and the presence of heavy metals unfavorable for plants (zinc, lead, mercury). Due to the possibility of contamination, including heavy metals, before introducing waste into the soil, it should be subjected to a detailed chemical analysis and treatment. The use of waste for the production of fertilizers allows for the reduction of the EU’s dependence on the import of nutrients from outside Europe, and is in line with the CE.

The paper presents an application of Life Cycle Assessment (LCA) method for the environmental evaluation of the technologies for the fertilizers production. LCA has been used because it enables the most comprehensive identifi cation, documentation and quantifi cation of the potential impacts on the environment and the evaluation and comparison of all signifi cant environmental aspects. The main objective of the study was to assess and compare two technologies for the production of phosphorus (P) fertilizers coming from primary and secondary sources. In order to calculate the potential environmental impact the IMPACT 2002+ method was used. The fi rst part of the LCA included an inventory of all the materials used and emissions released by the system under investigation. In the following step, the inventory data were analyzed and aggregated in order to calculate one index representing the total environmental burden. In the scenario 1, fertilizers were produced with use of an integrated technology for the phosphorus recovery from sewage sludge ash (SSA) and P fertilizer production. Samples of SSA collected from two Polish mono-incineration plants were evaluated (Scenario 1a and Scenario 1b). In the scenario 2, P-based fertilizer (reference fertilizer – triple superphosphate) was produced from primary sources – phosphate rock.

The results of the LCA showed that both processes contribute to a potential environmental impact. The overall results showed that the production process of P-based fertilizer aff ects the environment primarily through the use of the P raw materials. The specifi c results showed that the highest impact on the environment was obtained for the Scenario 2 (1.94899 Pt). Scenario 1a and 1b showed the environmental benefi ts associated with the avoiding of SSA storage and its emissions, reaching -1.3475 Pt and -3.82062 Pt, respectively. Comparing results of LCA of P-based fertilizer production from diff erent waste streams, it was indicated that the better environmental performance was achieved in the scenario 1b, in which SSA had the higher content of P (52.5%) in the precipitate. In this case the lower amount of the energy and materials, including phosphoric acid, was needed for the production of fertilizer, calculated as 1 Mg P2O5. The results of the LCA may play a strategic role for the decision-makers in the aspect of searching and selection of the production and recovery technologies. By the environmental evaluation of diff erent alternatives of P-based fertilizers it is possible to recognize and implement the most sustainable solutions.